Quadratic Equation! Please Help!

Question

Solve for x where 0 ≤ x ≤ pi.

sec^2 x + 3 sec + 2 = 0.

(the answers should be given as fractions, from least to greatest)

Answer 1

sec²x + 3secx + 2 = 0

(secx + 2)(secx + 1) = 0

secx = -2 or secx = -1

So, cosx = -1/2 or -1.

If cosx = -1, then x = π

If cosx = -1/2, then x = 2π/3

Solutions in the interval [0, π]: 2π/3, π